The group that's assembled for this meeting is not struggling with alcohol, drugs, sex addition or gambling. They're part of Starborn, an alien experience and awareness support group, catering to those who say they've been abducted by aliens.

Many people have wondered: are earthlings living on a speck of dust -- alone in the infinite universe or are there other intelligent life forms out there in the cosmos?

Nearly half of all Americans and millions more globally believe we're not alone, according to a 2000 ABC poll. While 40 million Americans say they have seen or know someone who has seen an unidentified flying object, or UFO, a growing number believe they've actually met aliens.

Abducted by Aliens: Twins Tell Their Story

Audrey and Debbie not only said that aliens exist, but that they've made contact with them. The twins said it started when they were young.

"I was probably about 5 years old or so ... and a bright blue light would come in to the room and the door would open, and there would be like, a foggy kind of misty blue light, just shining through the whole house," Audrey said. "And these two figures would come in. There would be a tall one, they had black capes, but they were bald and had big eyes."

Audrey and her sister call their visitors "The Bald Men," but they're better known in UFO circles as "The Greys," a race of extraterrestrials, categorized by the grayish color of their skin.

The twins' first encounter with aliens, they say, came during childhood and continued into adulthood. They also believe they've been abducted together on the same spaceship -- only to compare stories afterwards.

"We have been together on abductions," Audrey said. "We have been up in crafts and seen our house from above. So we realized they are not from here. They are very good at mind erasing or whatever you want to call it. They'll leave you with bits and pieces of things you can remember. So we do remember certain things of being there together."

When asked why aliens would continue to abduct them together, the twins had no explanation.

Extraterrestrials Can Embody People's Fears

No matter what anyone else believes, people like Audrey and Debbie are convinced that what they've witnessed is real.

"I remember one time being on a spaceship and standing there on the spaceship and the floor and the walls disappeared. And I was staring at the Earth," Debbie said.

They said they realize their stories sound too fantastic and, at times, like the stuff of sci-fi blockbusters.

In science fiction, aliens are often anthropomorphic and benign creatures, like "E.T.," "My Favorite Martian," the classic "Star Trek" television series or the hit movie "Close Encounters of the Third Kind."

But extraterrestrials can also embody people's fears, looking radically different from human life.

Pop culture depictions of aliens don't seem to be slowing down. On cable, there's the acclaimed mini-series "Torchwood: Children of Earth," where the aliens' sinister thoughts are spoken through possessed children. And this fall, ABC will add a new series to the list of those on creatures from outer space.

The members of Starborn believe, however, that this is not just the stuff of science fiction, but fact. They said that coming forward with their beliefs is challenging.

'Experiencers' Come Forward With Beliefs

Terrell Copeland, a former U.S. Marine, traveled the farthest to attend the "secret" meeting, driving 600 miles from rural Virginia. Copeland's foray into the paranormal began two years ago with a UFO sighting he said was captured on his cell phone from his apartment in downtown Suffolk, Va.

"It was an orb of light," he said. "Just a big ball of light. It wasn't moving. One was solid white. The other was directly across the street from it ... up 300 feet above ground and was changing colors very rapidly.

"This is ... this is not usual. Something's wrong here. Maybe I am in over my head. I'm not supposed to be looking at this stuff," Copeland, 27, who drives forklifts at a warehouse for a living, recalled thinking.

But after the video of what Copeland said he witnessed in the sky was posted on YouTube, he said a strange visitor came to his front door.

"I woke up from the nap by the sound of someone trying to enter my apartment," he said. "And I said, 'Who is it?' There was no answer. Still just, you know, you could see the door knob moving and like a scratching at the door. And I keep a firearm. It was on my table. And my thought was to get up and check.

"I was in complete paralysis. The only things I could move were my eyes. And I heard a voice through the door say, 'You don't need that weapon. We won't harm.'"

Soon after, Copeland said he started experiencing what he calls "missing time." During a span of two nights, Copeland said, he missed four hours -- not as a result of sleep.

Spiritual Transformation

"When you see these object[s], and then you do the research and you see that there are so many people who have experienced the same thing as you ... you have to say to yourself ... maybe there is something to this," he said.

With the number of unexplained UFO sightings mounting, Copeland began keeping a log and sketching what he believes he witnessed during the "missing time" episodes.

"I was a in a room and I saw a woman who did not have complete human features," he recalled from the night he said he was abducted in 2006. "She had the typical black eyes that you hear about. She had an elongated skull. And that startled me. And the next memory I have is me standing on my balcony waving at this cylinder-shaped ship."

Copeland said that his experiences with aliens have spiritually transformed him.

"I just want to be a better person because if I feel if someone from above took notice of me ... then maybe I'm doing something right. And if I'm doing something right, maybe I can do it better," he said.

Growing Number Believe They Have Been Abducted

Copeland's otherworldly convictions are shared by thousands of believers. Hundreds flocked to the national convention of the Mutual UFO Network, or MUFON, in Denver this month to share their experiences with like-minded believers.

Stace Tussel, a single working mother and cum laude college graduate, has been reluctant to talk about her close encounters with extraterrestrials.

"I'm not necessarily fearful," she said. "I'm a bit nervous about how people may react. I do believe that I have experienced contact with non-human intelligence."

Tussel said she has videos and scars to prove it.

"I've had multiple witness sightings or experiences, but also marks that would show up on my body -- scars like the one on my finger," Tussel said. "I did wake up one time with three red diagonal lines. I've woken up with the handprints and fingerprints that I couldn't have made myself and nobody else could have made myself."

When asked if she's simply a more vivid dreamer than other people, Tussel said, "I don't know if dreaming would cause a stigmata-type effect where you're getting bodily scars or marks."

Tussel, an education consultant, blogs in her spare time about UFOs and crop circles. While many have been proven to be man-made hoaxes, she believes some crop circles could be the result of an alien spacecraft or extraterrestrial communication.

She doesn't care for the phrase "alien abduction," opting instead to call herself an "experiencer."

"I don't believe I was taken against my will," she said. "I believe that all my life, I've been prepared to share information, to experience information and contact with non-human intelligence."

Psychologists Say Media Images Re-Enacted in Dreams

But she prefers to leave the details of her experiences to the imagination.

"I don't want to go into too much detail on certain kinds of beings that I saw because of the graphic nature of some of the things that I saw and experienced," she said.

While Tussel and others are thoroughly convinced, psychologists say the media-generated images of alien kidnappings can become easily engrained in our subconscious and then vividly re-enacted in our dreams.

"What tends to be similar is they come in the night, they take you some place, you're in a spaceship," Harvard University psychology researcher Susan Clancy said. "The aliens tend to look the same, which is that sort of greenish, triangular head, big eyes and they perform medical or sexual experiments on you."

Clancy and Richard McNally, who conduct psychological research examining false memories, believe a common disorder called sleep paralysis can explain why so many self-proclaimed "abductees" are absolutely convinced what they've experienced is real.

"A lot of people who had it think they're going crazy or they think that there are aliens or they think that there are ghosts out there," Clancy said. "And they're kind of freaked out."

Experts say sleep paralysis, the feeling of being awake, but unable to move during sleep, is quite common. Sufferers say they feel as if they're totally paralyzed -- a symptom that parallels what abductees like Copeland describe during their experiences with alleged extraterrestrial life.

"I couldn't move," Copeland said. "I was in complete paralysis, the only thing I could move were my eyes."

Clancy, herself, suffered from sleep paralysis and admitted that the feeling was so powerful that, for a moment, she was also convinced that her visions were real.

"It was so powerful at the time," she said. "While I'm levitating in the air -- that's what it felt like -- and spinning like a rotisserie chicken. I had this feeling that something was a presence. And I was thinking, 'Oh, my God, it's real.' But then it was over and then I woke up."

But for the majority of believers, Clancy said, their visions are likely facets of their imagination.

The abductees or experiencers ABC News spoke to reject any scientific explanation, asserting their belief that what they've been through is real.

"I can't sit here and tell you that I'm 100 percent sure what I say happened, happened," Copeland said. "It could be sleep paralysis. But I highly doubt it.

"I can remember vividly where I was, what I was doing and I was not awake. I could feel I was actually there."